1. Studies in the atmospheric monitoring at the Pierre Auger Observatory using the upgraded Central Laser Facilitymarko zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Carlos Medina-Hernandez, 2015, published scientific conference contribution Abstract: The Fluorescence Detector (FD) at the Pierre Auger Observatory
measures the intensity of the scattered light from laser tracks
generated by the Central Laser Facility (CLF) and the eXtreme
Laser Facility (XLF) to monitor and estimate the vertical
aerosol optical depth (τ(z,t)). This measurement is needed to
obtain unbiased and reliable FD measurements of the arrival
direction and energy of the primary cosmic ray, and the depth
of the maximum shower development. The CLF was upgraded
substantially in 2013 with the addition of a solid state laser,
new generation GPS, a robotic beam calibration system, better
thermal and dust isolation, and improved software. The upgrade
also included a back-scatter Raman LIDAR to measure τ(z,t).
The new features and applications of the upgraded instrument
are described. These include the laser energy calibration
and the atmospheric monitoring measurements. The first τ(z,t)
results and comparisons after the upgrade are presented using different methods. The first method compares the FD hourly
response to the scattered light from the CLF (or XLF) against
a reference hourly profile measured during a clear night where
zero aerosol contents are assumed. The second method simulates
FD responses with different atmospheric parameters and selects the parameters that provide the best fit to the actual FD
response. A third method uses the new Raman LIDAR receiver
in-situ to measure the back-scatter light from the CLF laser.
The results show a good data agreement for the first and second
methods using FD stations located at the same distance from the
facilities. Preliminary results of τ(z,t) using the Raman LIDAR
are presented as well.
Found in: ključnih besedah
Summary of found: ...The Fluorescence Detector (FD) at the Pierre Auger Observatory
measures...
Keywords: Pierre Auger Observatory, extensive air showers, the Fluorescence Detector, atmospheric monitoring, vertical aerosol optical depth, the Central Laser Facility, the eXtreme Laser Facility
Published: 03.03.2016; Views: 3968; Downloads: 175
 Fulltext (3,96 MB) |
2. Automated procedures for the Fluorescence Detector calibration at the Pierre Auger Observatorymarko zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Gaetano Salina, 2015, published scientific conference contribution Abstract: The quality of the physics results, derived from the analysis
of the data collected at the Pierre Auger Observatory depends
heavily on the calibration and monitoring of the components of
the detectors. It is crucial to maintain a database containing complete information on the absolute calibration of all
photomultipliers and their time evolution. The low rate of the
physics events implies that the analysis will have to be made
over a long period of operation. This requirement imposes a
very organized and reliable data storage and data management
strategy, in order to guarantee correct data preservation and
high data quality. The Fluorescence Detector (FD) consists of
27 telescopes with about 12,000 phototubes which have to be
calibrated periodically. A special absolute calibration system
is used. It is based on a calibrated light source with a
diffusive screen, uniformly illuminating photomultipliers
of the camera. This absolute calibration is performed every few
years, as its use is not compatible with the operation of the
detector. To monitor the stability and the time behavior,
another light source system operates every night of data
taking. This relative calibration procedure yields more than
2×10[sup]4 raw files each year, about 1 TByte/year. In this
paper we describe a new web-interfaced database architecture
to manage, store, produce and analyse FD calibration data.
It contains the configuration and operating parameters of the
detectors at each instant and other relevant functional
parameters that are needed for the analysis or to monitor
possible instabilities, used for the early discovery of
malfunctioning components. Based on over 10 years of
operation, we present results on the long term performance
of FD and its dependence on environmental variables. We also
report on a check of the absolute calibration values by
analysing the signals left by stars traversing the FD field of
view.
Found in: ključnih besedah
Keywords: Pierre Auger Observatory, Fluorescence Detector, detector calibration and monitoring, automated calibration procedure
Published: 03.03.2016; Views: 3492; Downloads: 192
Fulltext (1,06 MB) |
3. NOVEL APPROACHES FOR THE DETERMINATION OF BIOGENIC AMINES IN FOOD SAMPLESSara Budal, Mitja Martelanc, Mojca Žorž, Mladen Franko, 2017, original scientific article Abstract: In this work, new analytical approaches for determination of biogenic amines in wines were developed.
For the first time, we studied the derivatization of BAs in wines with naphthalene- 2,3-dicarboxaldehyde (NDA) and with dabsyl chloride (DBS) and analysis of derivatized BAs by HPLC coupled to fluorescence (HPLC-NDA-FL) and thermal lens spectrometry (HPLC-DBS-TLS) detectors. The sensitivity of the two methods (LODs HPLC-NDA-FL in the range 27-73 μg/L; LODs HPLC-DBS-TLS in the range 3.4-11 μg/L) was higher than that of the official method for biogenic amines in wines, OIV-MA-AS315-18 (60-77 μg/L). For its best performances, the HPLC-DBS-TLS technique was applied to the analysis of putrescine, cadaverine, histamine and tyramine in two white wine samples. Additionally, exploiting the Berthelot reaction, the TLS fast screening of biogenic amines in wines, following the release of ammonia by transglutaminase, was also proposed. This approach allowed us to determine total biogenic amount content in concentrations below 0.1 mg/L, expressed as equivalents of histamine.
Found in: ključnih besedah
Summary of found: ...of derivatized BAs by HPLC coupled to fluorescence (HPLC-NDA-FL) and thermal lens spectrometry (HPLC-DBS-TLS) detectors....
Keywords: biogenic amines, NDA, liquid chromatography, TLS, fluorescence, wine
Published: 02.11.2017; Views: 3681; Downloads: 253
Fulltext (441,06 KB) |
4. Improvements to aerosol attenuation measurements at the Pierre Auger ObservatoryMax Malacari, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, published scientific conference contribution Found in: ključnih besedah
Summary of found: ...aerosol attenuation measurements, Pierre Auger Observatory, fluorescence detector...
Keywords: aerosol attenuation measurements, Pierre Auger Observatory, fluorescence detector
Published: 19.02.2018; Views: 4093; Downloads: 160
Fulltext (1,96 MB) |
5. Mass composition of cosmic rays with energies from 10^17.2 eV to 10^20 eV using surface and fluorescence detectors of the Pierre Auger ObservatoryGašper Kukec Mezek, 2018, published scientific conference contribution Abstract: Ultra-high-energy cosmic rays (UHECRs) are highly energetic particles with EeV energies, exceeding the capabilities of man-made colliders. They hold information on extreme astrophysical processes that create them and the medium they traverse on their way towards Earth. However, their mass composition at such energies is still unclear, because data interpretation depends on our choice of high energy hadronic interaction models. With its hybrid detection method, the Pierre Auger Observatory has the possibility to detect extensive air showers with an array of surface water-Cherenkov stations (SD) and fluorescence telescopes (FD). We present recent mass composition results from the Pierre Auger Collaboration using observational parameters from SD and FD measurements. Using the full dataset of the Pierre Auger Observatory, implications on composition can be made for energies above 10^17.2 eV.
Found in: ključnih besedah
Keywords: astroparticle physics, ultra-high energy cosmic rays, extensive air showers, mass composition, Pierre Auger Observatory, fluorescence telescopes, water-Cherenkov stations
Published: 24.05.2019; Views: 2578; Downloads: 100
Fulltext (573,00 KB) |
6. Mineral element composition in grain of awned and awnletted wheat (Triticum aestivum L.) cultivars tissue-specific iron speciation and phytate and non-phytate ligand ratioHiram Castillo Michel, Iztok Arčon, Paula Pongrac, Katarina Vogel-Mikuš, 2020, original scientific article Abstract: In wheat (Triticum aestivum L.), the awns—the bristle-like structures extending from
lemmas—are photosynthetically active. Compared to awned cultivars, awnletted cultivars produce
more grains per unit area and per spike, resulting in significant reduction in grain size, but their
mineral element composition remains unstudied. Nine awned and 11 awnletted cultivars were
grown simultaneously in the field. With no difference in 1000-grain weight, a larger calcium and
manganese—but smaller iron (Fe) concentrations—were found in whole grain of awned than in
awnletted cultivars. Micro X-ray absorption near edge structure analysis of different tissues of
frozen-hydrated grain cross-sections revealed that differences in total Fe concentration were not
accompanied by differences in Fe speciation (64% of Fe existed as ferric and 36% as ferrous species) or
Fe ligands (53% were phytate and 47% were non-phytate ligands). In contrast, there was a distinct
tissue-specificity with pericarp containing the largest proportion (86%) of ferric species and nucellar
projection (49%) the smallest. Phytate ligand was predominant in aleurone, scutellum and embryo
(72%, 70%, and 56%, respectively), while nucellar projection and pericarp contained only non-phytate
ligands. Assuming Fe bioavailability depends on Fe ligands, we conclude that Fe bioavailability from
wheat grain is tissue specific.
Found in: ključnih besedah
Summary of found: ...biofortification, phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry,
phosphorus, sulphur, nicotianamine...
Keywords: biofortification, phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry, phosphorus, sulphur, nicotianamine
Published: 16.01.2020; Views: 2098; Downloads: 0
Fulltext (2,63 MB) |
7. The multi-purpose role of hairiness in the lichens of coastal environments: Insights from Seirophora villosa (Ach.) FrödénElisabetta Bianchi, Renato Benesperi, Ilaria Colzi, Andrea Coppi, Lorenzo Lazzaro, Luca Paoli, Alessio Papini, Sara Pignattelli, Corrado Tani, Pamela Vignolini, Cristina Gonnelli, 2019, original scientific article Abstract: The fruticose epiphytic lichen Seirophora villosa, strictly associated with Juniperus shrublands in the
Mediterranean basin, was used to investigate the role of hairiness on a lichen thallus, as a characteristic morphological
trait. We evaluated the effect of hair removal on the physiological parameters of a set of samples,
during desiccation and on exposure to different salt concentrations. Hairy thalli were less affected by salt,
suggesting that during dehydration, the presence of hair protects the thallus from light irradiance, oxidative
stresses and the lipid peroxidation generated by free radicals, and could offer passive, but selective, water
control. Our results showed that hair could not only increase thallus surface and promote water absorption when
availability is low, but could also repel the salt dissolved in water by activating a passive resistance mechanism,
by preventing salt entering.
Found in: ključnih besedah
Summary of found: ...Antioxidant activity
Chlorophyll a fluorescence
Juniperus shrublands
Hair
MDA
Salt stress...
Keywords: Antioxidant activity
Chlorophyll a fluorescence
Juniperus shrublands
Hair
MDA
Salt stress
Published: 20.04.2020; Views: 1979; Downloads: 0
Fulltext (9,03 MB) |
8. Study of Ultra-High Energy Cosmic Ray composition using Telescope Array’s Middle Drum detector and surface array in hybrid modeJon Paul Lundquist, R.U. Abbasi, 2015, original scientific article Abstract: Previous measurements of the composition of Ultra-High Energy Cosmic Rays (UHECRs) made by the High Resolution Fly’s Eye (HiRes) and Pierre Auger Observatory (PAO) are seemingly contradictory, but utilize different detection methods, as HiRes was a stereo detector and PAO is a hybrid detector. The five year Telescope Array (TA) Middle Drum hybrid composition measurement is similar in some, but not all, respects in methodology to PAO, and good agreement is evident between data and a light, largely protonic, composition when comparing the measurements to predictions obtained with the QGSJetII-03 and QGSJet-01c models. These models are also in agreement with previous HiRes stereo measurements, confirming the equivalence of the stereo and hybrid methods. The data is incompatible with a pure iron composition, for all models examined, over the available range of energies. The elongation rate and mean values of are in good agreement with Pierre Auger Observatory data. This analysis is presented using two methods: data cuts using simple geometrical variables and a new pattern recognition technique.
Found in: ključnih besedah
Summary of found: ...Energy Cosmic Rays, Cosmic ray composition, Atmospheric fluorescence, Extensive air shower array, Hybrid, Telescope Array...
Keywords: Ultra-High Energy Cosmic Rays, Cosmic ray composition, Atmospheric fluorescence, Extensive air shower array, Hybrid, Telescope Array
Published: 24.04.2020; Views: 2210; Downloads: 0
Fulltext (3,45 MB) |
9. The energy spectrum of cosmic rays above 1017.2 eV measured by the fluorescence detectors of the Telescope Array experiment in seven yearsJ. P. Lundquist, R.U. Abbasi, 2016, original scientific article Abstract: The Telescope Array (TA) experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The fluorescence detectors at two stations of TA are newly constructed and have now completed seven years of steady operation. One advantage of monocular analysis of the fluorescence detectors is a lower energy threshold for cosmic rays than that of other techniques like stereoscopic observations or coincidences with the surface detector array, allowing the measurement of an energy spectrum covering three orders of magnitude in energy. Analyzing data collected during those seven years, we report the energy spectrum of cosmic rays covering a broad range of energies above 10^17.2eV measured by the fluorescence detectors and a comparison with previously published results.
Found in: ključnih besedah
Keywords: Cosmic rays, Ultra-high energy, Fluorescence detector, Energy spectrum, Ankle, GZK cutoff
Published: 27.04.2020; Views: 2007; Downloads: 0
Fulltext (1,23 MB) |
10. TA Anisotropy SummaryJ. P. Lundquist, K. Kawata, 2019, published scientific conference contribution Abstract: The Telescope Array (TA) is the largest ultra-high-energy cosmic-ray (UHECR) detector in the northern hemisphere. It consists of an array of 507 surface detectors (SD) covering a total 700 km^2 and three fluorescence detector stations overlooking the SD array. In this proceedings, we summarize recent results on the search for directional anisotropy of UHECRs using the latest dataset collected by the TA SD array. We obtained hints of the anisotropy of the UHECRs in the northern sky from the various analyses.
Found in: ključnih besedah
Summary of found: ...covering a total 700 km^2 and three fluorescence detector stations overlooking the SD array. In...
Keywords: cosmic radiation, UHE detector, fluorescence detector, surface, Telescope Array Experiment, anisotropy, experimental results
Published: 28.04.2020; Views: 2044; Downloads: 68
Fulltext (1,88 MB) |
